BLD: Build & test for MacOS arm64 arch with m1 runner

[yngve-sk]

Resolves #907

Relates to making ert runnable on arm64 arch on macos, depends on this also being arm64-compatible.

Note: Had to refactor the os-cibw_image mapping to to its own step in order to be able to exclude building macos-latest-xlarge,cp39 from build matrix. Do not know why 3.9 does not work, but resdata only supports python >= 3.10 for ARM, so we have no need for it anyway in the context of ert, so I suggest leaving the "make it work for 3.9 ARM" for a separate thing if anyone wants to do that.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (97b3f09) 80.10% compared to head (e7b06fa) 80.10%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1098 +/- ## ======================================= Coverage 80.10% 80.10% ======================================= Files 95 95 Lines 13428 13428 Branches 2183 2183 ======================================= Hits 10756 10756 Misses 1948 1948 Partials 724 724 ```

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